The Syrian army is moving to crush in blood the protesters calling for democracy and the overthrow of President Bashar al-Assad and his regime. Unburied bodies lie in the streets of Deraa, the city in the south which has been at the centre of the popular revolt.

Will the government succeed? The chances for the moment look evenly balanced, with almost everything depending on whether or not demonstrators continue to march and rally all over Syria despite the savage repression. There is also the possibility of divisions in the army, though less so than in many other Arab countries.

The uprising against police states, both republican and monarchical, in the Arab world is entering its fifth month without a decisive victory by either the powers-that-be or the protesters. In Tunisia and Egypt the political and military elite felt that, if they got rid of their geriatric leaders along with their families and cronies, they might prevent radical changes in the political and social status quo. In Bahrain the monarchy, aided by Saudi Arabia and other Sunni Gulf states, destroyed the pro-democracy movement and is terrorizing its supporters.

Syria is going down the same road as Bahrain. At the end of last week President Assad and his inner circle appear to have decided that such limited concessions as they were willing to make were only being interpreted as weakness. They gave orders to their security forces to shoot unarmed demonstrators and stamp out all signs of dissent on the streets.

Repression in Syria may work for the moment. The government has a core of support based on the Allawite minority, to which the Assad family and top military and political members of the regime belong. There are others who work for the state and fear change, as well as Christian and Druze minorities who do not believe opposition claims to be non-sectarian.

Overall, however, the police states in the Arab world, which have seemed so immoveable over the last 35 years, are fighting to survive. Before about 1975 there was an era of army coups d’etat, but these stopped as ferocious multi-layered security agencies turned military dictatorships into police states. East European intelligence agencies gave fraternal advice on how this could be done.

There was more to total state control than just keeping the army in its barracks. Censorship of all forms of media was pervasive as was control of all non-state agencies such as trade unions and political parties. Only the mosque retained some autonomy, which explains why opposition to autocracy so often took an Islamic form.

By this year the ingredients of repression had lost something of their old potency. Torturers and executioners still retained their ability to frighten. But regimes had lost their control over information and communications thanks to the internet, satellite television and even the humble mobile phone. One member of the Syrian opposition points out that when thousands in Hama were slaughtered by the forces of President Hafez al-Assad in 1982 there was not a single picture of even one of the bodies. Today pictures of the dead and wounded in Deraa and elsewhere in Syria are transmitted to the rest of the world within seconds of them being shot.

Of course governments can counter-attack and close down mobile phone networks and ban journalists from operating in Syria. But 100 satellite phones distributed by an opposition Syrian businessman make total control of information almost impossible to establish. The role of the internet in the Arab Awakening has been well-publicized, but that of satellite stations, notably al-Jazeera is underplayed. The US has every reason to be embarrassed by this since Washington spent years claiming that al-Jazeera’s criticism of US policy in Iraq after the invasion showed it must be linked to al-Qa’ida. An al-Jazeera cameraman was held in Guantanamo for six years so US interrogators could find out more about the television station.

Britain, France and Italy have now called on sanctions against Syria to show disapproval of the repression. But they should not do more because intrusive foreign intervention is likely to prove counter-productive. There are already signs of this in Libya. Justifiable action against impending massacre turns into imperial intervention. NATO air strikes against Colonel Gaddafi’s tanks advancing on the rebel stronghold of Benghazi have escalated into an air war, aided by foreign advisers on the ground, with the purpose of overthrowing the regime. In such an offensive the Libyan rebels, whatever their popular support and skill in media relations, may play only a walk on part.

It is worth recalling that most Afghans were pleased when the Taliban collapsed in 2001 and most Iraqis were glad to see the back of Saddam Hussein in 2003. But it did not follow that the opponents of autocracy were united, had real support or were less corrupt or more competent than their predecessors. Nor were Afghans or Iraqis prepared to see foreign armies determine who should hold power in their countries.

People whom Western states claim they are trying to aid for humanitarian reasons are understandably sceptical about how altruistic their motives really are. Their suspicions will only be confirmed by documents published this week by The Independent giving details of talks between the British government and BP and Royal Dutch Shell in 2002 on how to avoid US companies excluding them from exploiting Iraqi oil reserves.

There is a further reason why Britain and other foreign states should limit their involvement in the conflicts now raging in the Arab world. It is true that the struggle is primarily between popular protests or uprisings against vicious autocracies. But these crises have at least some aspects of a civil war: there are tribes which support Col Gaddafi and there are Syrians who believe that the opposition is more sectarian and Sunni-dominated than is evident from their human rights agenda.

It is right for Britain and its allies to protest at the butchery in Syria, though their criticism might carry more weight had they been equally vocal about torture, disappearances and killings in Bahrain. But this humanitarian zeal easily becomes a cover for wider intervention, because retreat is humiliating and therefore politically impossible, and the field cannot be left open to other competing interventionist powers. The outside world can mitigate, but should not try to change, what is happening in Syria.